Field
The present application relates generally to light emitting diodes, and more particularly, to apparatus providing beamforming and environmental protection for light emitting diode (LED) light sources.
Background
A light emitting diode comprises a semiconductor material impregnated, or doped, with impurities. These impurities add “electrons” and “holes” to the semiconductor, which can move in the material relatively freely. Depending on the kind of impurity, a doped region of the semiconductor can have predominantly electrons or holes, and is referred to as an n-type or p-type semiconductor region, respectively.
In LED applications, an LED semiconductor chip includes an n-type semiconductor region and a p-type semiconductor region. A reverse electric field is created at the junction between the two regions, which causes the electrons and holes to move away from the junction to form an active region. When a forward voltage sufficient to overcome the reverse electric field is applied across the p-n junction, electrons and holes are forced into the active region and combine. When electrons combine with holes, they fall to lower energy levels and release energy in the form of light. The ability of LED semiconductors to emit light has allowed these semiconductors to be used in a variety of lighting devices. For example, LED semiconductors may be used in general lighting devices for interior applications or in street lighting for exterior applications.
When using LED semiconductors in lighting devices for exterior applications, it is generally necessary to provide environmental protection to prevent damage from exposure to moisture or other environmental conditions. For example, exterior LED lighting is typically designed to meet industry standard Ingress Protection (IP) ratings that specify various levels of environmental protection. For example, an IP rating normally has two (or three) numbers that specify a level of protection from solid objects, liquids, and/or mechanical impacts. Typically, LED lighting devices for exterior use are designed to satisfy IP-65/66/67 ratings.
Both interior and exterior LED lighting devices may utilize beamforming lenses to produce light having a particular beam pattern. For example, roadway lights are typically designed to meet Illuminating Engineering Society of North America (IESNA) or International Commission on Illumination (CIE) standards.
These standards specify illumination patterns for pole mounted roadway lights. To meet these requirements, an exterior LED lighting device may utilize one or more optical lenses and/or reflectors to distribute the light emitted from the LED semiconductor to produce light having a desired illumination pattern.
The application of LED semiconductors in lighting devices may also require the use of additional components to provide alignment or heat dissipation. For example, the precise alignment of the LED semiconductor may be needed to facilitate beamforming. Furthermore, high powered LED semiconductors used in exterior lighting applications often generate heat which needs to be dissipated. As a result, additional heat dissipating components may also be used in these devices.
Conventional LED devices for exterior use typically have separate components, parts, and/or assemblies which are combined to provide the beamforming, environmental protection, alignment, and heat dissipation functions described above. However, such devices typically comprise a large number of parts and/or mounting components. Unfortunately, this may result in LED devices that may be expensive, complicated to assemble/disassemble, and may be difficult to maintain and/or repair.
Accordingly, what is needed is a simple and efficient way to meet the beamforming and environmental protection requirements for exterior LED light sources and which overcomes the problems of excessive components, expense, and complicated assembly associated with conventional LED devices.